Propulsion device of the walker type



Feb. 26, 1963 Filed Nov. 30, 1961 G. B. BARON ETAL PROPULSION DEVICE OFTHE WALKER TYPE 3 Sheets-Sheet l INVENTORS Feb. 26, 1963 a. B. BARONETAL PROPULSION DEVICE OF THE WALKER TYPE Filed Nov. 30, 1961 5Sheets-Sheet 2 ATTORNEYS Feb. 26, 1963 G. B. BARON ETAL PROPULSIONDEVICE OF THE WALKER TYPE 3 Sheets-Sheet 3 Filed Nov. 30, 1961 INVENTORSfieazye 3. 121mm 5 I [09/4110 1/. Jamie BY I WM 5 ATTORNEYS UnitedStates Patent 3,078,941 FROPULSION DEVICE 8F THE WALKER TYPE George B.Baron and Edwin W. Sankey, Marion, Ohio, as'signors to Universal Marion(Iorporation, Marion, Ohio, a corporation of Florida Filed Nov. 38,1961, Ser. No. 156,35?

6 Claims. (Cl. 136-43) This invention relates to propulsion devicesspecially adapted for use with heavy equipment, and particularly topropulsion devices of the walker type.

The general object of the present invention is to prtr vide a propulsionmeans of the walker type which will be an improvement over thosepreviously suggested.

A more specific object is the provision of mechanism of this type whichis capable of infinite adjustment to vary the shape and inclination ofthe orbital path defined by the connection between the mechanism andtread during operation.

A further object is to provide a walker which will supply the necessarymotion to the tread members without need for slides, towers, etc.

Other objects of the invention will become apparent from the followingdescription of one practical embodie ment thereof, when taken inconjunction with the drawings which accompany, and form part of, thisspecification.

In the drawings:

FIGURE 1 is a side elevation of a piece of heavy equipment provided withthe propulsion device of the resent invention;

FIGURE 2 is a perspective view of the operating mechanism at one side ofthe equipment, illustrating a portion of the drive for the mechanism anda portion of a tread carried by the mechanism;

FIGURES 3 and 4 show the mechanism in side elevation in two positions inits cycle of operation; and

FIGURES 5 to 7 show diagrammatically variations of the mechanism settingout the orbital movement paths obtained thereby.

In general, the invention contemplates providing a walker propulsionmechanism for heavy equipment which will have a double eccentric, orcrank, drive means, with a pair of links interconnecting the eccentrics,or cranks, and the tread member, to divide the load of the equipmentbetween two drive shafts.

Referring to the drawings in detail, the propulsion de vice is shown,for purpose of illustration, mounted upon a dragline excavator 1, whichincludes a platform 2 supporting the body portion 3 and pivotallymounted upon a circular base 4. The excavator is not shown in detail,and parts are broken away, but it has the usual boom 5 by which the dragbucket (not shown) is carried in a conventional manner. The boom ismounted at the rear of the platform, and the machine is designed to bemoved normally in the opposite direction.

Treads 6 are located at opposite sides of the machine for contact withthe ground at opposite sides of the circular base. The treads areconnected by links 7 and 8 with drive shafts 9 and 10 mounted upon theplatform. Only one tread and its drive have been shown, but it will beunderstood that this mechanism is duplicated on the opposite side of theplatform as in the mentioned previous patents.

Drive shafts 9 and 10 extend transversely of the platform and aresupported in suitable bearings 11 and 12. The shafts are relativelyshort, and carry spur gears 13 and 14, respectively, at their innerends. These gears mesh with a gear 15 mounted on the end of a principaldrive shaft 16, supported in appropriate bear- 3,078,941 Patented Feb.26, 1963 ings (not shown) and driven from a suitable power source (notshown) carried on the platform.

All of the above structure, with the exception of links 7 and 8, iscompletely shown in the patent to Busick et al., No. 2,541,496, and thatpatent can be referred to for the structural details which have beenomitted here to simplify the present disclosure.

As can be seen particularly well in FIGURE 2, the links 7 and 8 havetheir upper ends journalled, respectively, on the crank pins 17 and 18of the cranks 19 and 20, fixed to the ends of drive shafts 9 and 10. Thelower ends of the links are mounted upon a pivot pin 21 transverselybridging a yoke 22. In order for the two links to be positioned andoperate in the same vertical plane for balance, and to equalize the loadupon pivot pin 21, one of the links, as shown the link 8, may bebifurcated at its lower end so that it will straddle the lower end oflink 7. Yoke 22, in turn, has coaxial trunnions 23 projecting fro-m itsends, with their com.- mon axis lying normal to the axis of pivot pin21. Trunn-ions 23 are rotatably mounted in ears 24 upstanding from thetread 6. This mounting permits universal movement to the tread 6, sothat the tread is free to adapt its position to ground contour each timethe tread is placed upon the ground.

It'will be evident that with the above described linkage between thedrive shafts 9 and 10 and the tread, the tread will be lifted eachrotation of the drive shafts, moved forward and again moved down intoground contact. When the tread rests upon the ground, the remainingcycle of rotation of the cranks will result in pivotal movement of thecranks about the crank pins 17 and 18 and movement bodily of the driveshafts 9 and 10, upwardly and forwardly, to move the machine in aforward direction.

When cranks of the same length are employed and the cranks are arrangedon their respective drive shafts so as to lie parallel to one another,the movement described by pivot pin 21 in lifting and moving forward thetread will be a semi-circle. Similarly, the movement of the machine asit is raised and moved forward as the cranks pivot about the crank pins17 and 18 will be semi-circular.

The orbital path of movement of the pivot pin 21 can be changedconsiderably to increase the vertical lift or the horizontal steplength, as desired, by advancing one crank relative to the other, byusing cranks of different lengths, by using links of difierent length,by changing the spacing between cranks or the relative elevations of thecranks, or combination of these variations. In the illustratedembodiment, the rear crank has been advanced in the direction of crankrotation over the forward one. This will materially increase the forwardmovement of the machine each cycle of shaft rotation. As shown in thediagram of FIGURE 6, the plotted path of the pivot pin is generallyelliptical with its long axis extending horizontally. This not onlyincreases the forward length of the step ta-ken each cycle, but reducesthe height the machine need be lifted from the ground.

The benefit of lengthened step can be retained, and the long axis of theelliptical plotted path can be angularly adjusted by changing thelengths of the respective cranks. For example, FIGURE 7 illustrates anarrangement wherein the forward crank is larger than the rear one, andthe rear crank is advanced 45 relative to the forward one. This producesa fiat orbit having a longitudinal axis which is inclined forwardly.With this structure, the tread and the machine will each move forward ina trajectory which will progressively rise during a major portion of theforward motion, and lower at the end of the step.

which provides all of the advantages of prior structures,

and, at the same time, eliminates the need for slides or towers toobtain the proper tread advancing movement.

While in the above one practical embodiment of the invention has beendisclosed, it will be understood that the details of structure shown anddescribed are merely by way of illustration and the invention may takeother forms within the scope of the appended claims.

What is claimed is:

1. A propulsion device of the walker type for heavy equipment having aplatform and a power source on the platform comprising, a pair ofparallel drive shafts mounted transversely of the platform at one sideof the platform and operatively connected to the power source forsimultaneous rotation at the same speed, means carried by the shaftsradially removed from the axes of the respective shafts to provideeccentric driving members, a tread at the side of the platform extendinglongitudinally of the platform, and a pair of links each pivoted at oneend to the tread, one link of the pair of links having its opposite endjournalled on the eccentric driving member of one shaft of the pair ofshafts and the other link of the pair of links having its opposite endjournalled on the eccentric driving member of the other shaft of thepair of shafts.

2. A propulsion device of the walker type as claimed in claim 1 whereinone of the eccentric driving members is advanced in the direction ofshaft rotation relative to the other eccentric driving member.

3. A propulsion device of the walker type as claimed in claim 1 whereinthe eccentric driving members are cranks.

4. A propulsion device of the walker type as claimed in claim 1 wherein,the eccentric driving member of one shaft of the pair of shafts isspaceda greater radial distance from the axis of the shaft that carries itthan the radial spacing of the other eccentric driving member from theaxis of the shaft that carries it.

5. A propulsion device of the walker type for heavy equipment having aplatform and a power source on the platform comprising, a principaldrive shaft mounted transversely of the platform and operativelyconnected to the power source, a pair of parallel drive shafts mountedon the platform at each side of the platform,

means interconnecting the principal drive shaft and the pairs ofparallel drive shafts to rotate each shaft of the pairs of shafts at thesame speed in the same direc- =tion, means carried by each shaft of thepairs of shafts radially removed from the axes of the shafts that carrythem to provide eccentric driving members, a tread member at each sideof the platform extending longitudinally of the platform, and a pair oflinks pivotally connected at one end to each tread member, the links ofeach pair having their opposite ends journalled to the eccentric drivingmembers of the pair of drive shafts at the same side of the platform asthe tread member to which the respective links are connected.

6. A propulsion device of the walker type as claimed in claim 5 wherein,the eccentric driving members are cranks.

References Cited in the file of this patent UNITED STATES PATENTS

1. A PROPULSION DEVICE OF THE WALKER TYPE FOR HEAVY EQUIPMENT HAVING APLATFORM AND A POWER SOURCE ON THE PLATFORM COMPRISING, A PAIR OFPARALLEL DRIVE SHAFTS MOUNTED TRANSVERSELY OF THE PLATFORM AT ONE SIDEOF THE PLATFORM AND OPERATIVELY CONNECTED TO THE POWER SOURCE FORSIMULTANEOUS ROTATION AT THE SAME SPEED, MEANS CARRIED BY THE SHAFTSRADIALLY REMOVED FROM THE AXES OF THE RESPECTIVE SHAFTS TO PROVIDEECCENTRIC DRIVING MEMBERS, A TREAD AT THE SIDE OF THE PLATFORM EXTENDINGLONGITUDINALLY OF THE PLATFORM, AND A PAIR OF LINKS EACH PIVOTED AT ONEEND TO THE TREAD, ONE LINK OF THE PAIR OF LINKS HAVING ITS OPPOSITE ENDJOURNALLED ON THE ECCENTRIC DRIVING MEMBER OF ONE SHAFT OF THE PAIR OFSHAFTS AND THE OTHER LINK OF THE PAIR OF LINKS HAVING ITS OPPOSITE ENDJOURNALLED ON THE ECCENTRIC DRIVING MEMBER OF THE OTHER SHAFT OF THEPAIR OF SHAFTS.